"Bill Marimow is one of the most respected journalists in the nation, and his return reinforces the company's commitment to aggressive investigative reporting," Greg Osberg, chief executive of Philadelphia Media Network, said in a statement.
Stan Wischnowski, 49, The Inquirer's current editor, will remain with the newspaper and continue serving as one of Marimow's top deputies. Marimow is expected to begin work May 1.
Wischnowski noted that the newspaper's coverage of violence in Philadelphia schools recently won a prestigious first-place award from Investigative Reporters and Editors, and that The Inquirer's sports section was ranked in the nation's Top 10 by Associated Press Sports Editors.
He praised the staff for producing "quality journalism in the last 18 months under very difficult circumstances."
"Faced with the tough recession and hedge-fund owners, this staff could've lost its focus, but the journalism remains strong, and I am very proud of the newsroom's accomplishments."
Marimow's return is the latest twist in events that have shaken the city's largest news organization, which has experienced five ownership changes, four changes of editors, and several painful staff reductions since 2006.
After banks and hedge funds bought the newspaper out of bankruptcy in 2010, Marimow was demoted and returned to reporting. In June, he joined the faculty of the Walter Cronkite School of Journalism and Mass Communications at Arizona State University to lead the Carnegie-Knight News21 in-depth digital-journalism program.
Marimow, who sold his Center City house in August and bought a condominium in Scottsdale, said leaving the academic world will be hard.
"Being a part of this has been a privilege," he said in a phone interview Wednesday.
Marimow said he had been in discussions with Osberg and several members of the new ownership group in recent weeks.
"I believe the local owners may have suggested it would be great if I could return. Now, I'm coming back."
Osberg, who removed Marimow in 2010 a few days after taking control of the newspaper, said then that he wanted an editor with more digital-media experience.
Wednesday afternoon, Osberg said in an e-mail, "Bill and I have discussed the importance of our digital future, and he fully embraces the idea of working in a collaborative manner with our digital team at Philly.com."
The new owners have pledged a policy of strict non-interference with news decisions.
Marimow, a Havertown native, worked at the former Evening Bulletin before joining The Inquirer in 1972. He won two Pulitzers for his investigations of abuses by police, one in 1977 in partnership with another reporter and a second in 1985.
In 1993, he joined the Baltimore Sun as metro editor and rose to editor-in-chief. Though the newspaper won a string of Pulitzers, he was fired after a new publisher took the helm in 2004.
Marimow was hired at National Public Radio that year as managing editor for national news and later served as vice president of news. He rejoined The Inquirer in 2006, when new owners hired him as editor.
Representatives of the Newspaper Guild of Greater Philadelphia, which represents newsroom, advertising, and circulation workers and sometimes clashed with Marimow during his first tenure as editor, declined to comment about his return.
Marimow will take over a smaller newsroom than the one he left last year. The company cut 37 newsroom positions in March at the two newspapers and Philly.com. The Inquirer newsroom now has about 240 employees, down from more than 600 in the late 1990s.
Marimow said the "breadth of coverage will be a little smaller" because of the smaller staff, but promised to continue to pursue deep stories.
"My philosophy has always been to do what we do excellently," he said. "We will try to produce indispensible content without covering every planning board meeting in the region.
Contact Andrew Maykuth at 215-854-2947, @Maykuth on Twitter or firstname.lastname@example.org